Technical Field
Certain embodiments of the invention relate to a regenerative refrigerator.
Description of Related Art
A regenerative refrigerator is used in order to cool an object to be cooled from about 100 K (kelvin) to about 4 K, for example. As regenerative refrigerators, there are, for example, a Gifford McMahon type (GM) refrigerator, a pulse tube refrigerator, a Stirling refrigerator, a Solvay refrigerator, and the like. The regenerative refrigerator is used for cooling of a superconducting magnet, a detector, or the like, or as a cryopump.